The invention relates to means for starting a gas turbine plant, and, more particularly, to such a starting means that includes an ignition combustion chamber connected in parallel with a main combustion chamber to drive a turbine of the turbine plant during a turbine start-up interval when a fluidized bed of combustible material in the main combustion chamber is being heated to an ignition temperature.
It is known to apply the combustion gases of an ignited, fluidized bed of combustible material to drive a turbine and associated compressor of a turbine plant. However, in order to start such a turbine plant in operation, it is necessary to utilize an auxiliary heating apparatus for initially heating the combustible material of the fluidized bed to an ignition temperature over a start-up interval. Likewise, auxiliary driving apparatus must be employed to operate the turbine and the compressor so that compressed air may be applied to support the combustion of at least the fluidized bed during the start-up interval. Such auxiliary driving apparatus may include an auxiliary motor for operating the turbine during the start-up interval or an injector apparatus for blowing high pressure air from an air receiver into the compressor of the turbine to operate the compressor and the turbine.
Prior art systems for starting gas turbines have the disadvantage that the associated auxiliary driving apparatus must be relatively powerful in order to drive the turbine and compressor during the substantial interval when the combustible fuel in the main combustion chamber is being heated to its ignition temperature. Thus, such driving apparatus tends to be relatively large and expensive, even if the amount of fluidized combustible fuel in the main combustion chamber is reduced during the turbine start-up interval and the duration of the start-up interval and driving power requirements for the turbine and compressor are thereby reduced. Moreover, for reasons of practical economy, it is generally not feasible to utilize ignition start-up apparatus having sufficient power to drive even a lightly loaded turbine during the start-up interval.
Accordingly, it is an object of the invention to provide a simple and efficient means for operating a turbine and an associated compressor in a gas turbine plant under no load or light load conditions, while the combustible material in a fluidized bed in a main combustion chamber is being heated to an ignition temperature.
A further object of the invention is to provide such a turbine start-up means that may operate to drive a turbine and associated compressor during the start-up interval without requiring a reduced amount of combustible material in the fluidized bed of the main combustion chamber.
These and other objects of the invention will become apparent from a review of the detailed specification which follows and a consideration of the accompanying drawings.